org.argeo.cms.ee/src/org/argeo/cms/servlet/ServletUtils.java

   1 package org.argeo.cms.servlet;
   2
   3 import static org.argeo.cms.http.HttpHeader.VIA;
   4 import static org.argeo.cms.http.HttpHeader.X_FORWARDED_HOST;
   5
   6 import java.net.URI;
   7 import java.util.ArrayList;
   8 import java.util.Enumeration;
   9 import java.util.List;
  10
  11 import javax.servlet.http.HttpServletRequest;
  12
  13 /** Servlet utilities. */
  14 public class ServletUtils {
  15
  16         /**
  17          * The base URL for this query (without any path component (not even an ending
  18          * '/'), taking into account reverse proxies.
  19          */
  20         public static StringBuilder getRequestUrlBase(HttpServletRequest req) {
  21                 List<String> viaHosts = new ArrayList<>();
  22                 for (Enumeration<String> it = req.getHeaders(VIA.getHeaderName()); it.hasMoreElements();) {
  23                         String[] arr = it.nextElement().split(" ");
  24                         viaHosts.add(arr[1]);
  25                 }
  26
  27                 String outerHost = viaHosts.isEmpty() ? null : viaHosts.get(0);
  28                 if (outerHost == null) {
  29                         // Try non-standard header
  30                         String forwardedHost = req.getHeader(X_FORWARDED_HOST.getHeaderName());
  31                         if (forwardedHost != null) {
  32                                 String[] arr = forwardedHost.split(",");
  33                                 outerHost = arr[0];
  34                         }
  35                 }
  36
  37                 URI requestUrl = URI.create(req.getRequestURL().toString());
  38
  39                 boolean isReverseProxy = outerHost != null && !outerHost.equals(requestUrl.getHost());
  40                 if (isReverseProxy) {
  41                         String protocol = req.isSecure() ? "https" : "http";
  42                         return new StringBuilder(protocol + "://" + outerHost);
  43                 } else {
  44                         return new StringBuilder(requestUrl.getScheme() + "://" + requestUrl.getHost()
  45                                         + (requestUrl.getPort() > 0 ? ":" + requestUrl.getPort() : ""));
  46                 }
  47         }
  48
  49         /** singleton */
  50         private ServletUtils() {
  51         }
  52 }